Multiple sheet expanded metal air filter



, I vJuly 8 1952 2 G. o. SMITH 2,602,521

MULTIPLE SHEET EXPANDED METAL AIR FILTER Filed Sept. 2l, 1950 vnvVENToR. GLENN o. SMITH @aA/@MW ATTORNEY like.

Patented July 8, 1952 't 1 lr2,602,521. I v

Filter 1Cor-poration,

ofailllinois, Y

The present invention relates generally to Ilters and more particularly to filters 'designed 'to remove dust, dirtl andathe. like from air, Laslin. air .conditioning systems, vand to'lters adaptedfor; use in tkitchen Ventilating systems or the like where it isdesired to remove grease andv theflike from the vapors `rexhausted intoLthe dischargev ducts so as tore'ducethe lire hazards'.

The object and general nature of my invention is the provision of a filter formed of ,several layers .of expanded metalsheets, preferablyv vallum- Vinem; so constructed'vand f'arran'gedfthat the Y expanded metal sheets having the'l'argest Iopenings :are disposed at the intake side of the filter and the other sheets having smaller openings are so` disposed that the openings progressively decrease `ini-size toward the dischargeside of thev filter. 1i

An additional feature of 'this invention'isthe provision of? a lter for removing grease andthe like from grease-laden gases and vapors Abefore passing them into the associated discharge ducts, in which the filter elements are formed of aluminum or other metal of high heat conductivity, whereby in the caseof fire the heat will be dissipated sufliciently to prevent combustion of any gases or vapors beyond the filter. n f, A further feature of this invention is the provision ofa fllterhaving layers of expanded metal sheets, each sheet being so constructed that at least certain of the edges of each openingare roughenedlor drawn out'into 'a multiplicity of small points Whichaserve to entrap and remove dustand'the like from the air passing through thefiilter.A Also, such roughened, pointedV or serrated edges serve to entrap grease particles and the like from grease-laden vapors lpassed through the'lter. 7 i

It is an additional feature of this invention to so shape the mesh of the expanded metal sheets as to form a plurality 4of small pockets or dust-catching depressionswhich act vtotrap dust, soot, pollen, grease particles and the like. A filter constructed in this way is admirably adapted to be used without the usual coating of oil or other viscous material, termed a dry filter, especially when removing grease particles or the Thus, the present filter may be used as a dry filter, in which the pockets and roughened edges mechanically strain or screen out dust and dirt particles or the like, or as a viscous filter in which a multiplicity of small pockets and sharpened or feathered edges materially increase the oil-holding capacity of the lter, and hence also its dust-holding capacity so that the filter ApplicationS'eptenberl,1950, Serial No.' 1862985 folien.e (o1. msg-'roi does not have to be fcleaned or renewed as often as ordinary-filters. l l

An additional feature ofV this invention is the -provision of a filter having both the frame and the `iilter elements of fthe same metal, such as aluminum, preferably, so vthat the filter is not affected by water or humidity in the-air passing through the iilter, =nor is the'unit subject to cor-r rosion due l.to electrolysis resulting from ythe action of dissimilar metalsdn the presence of moisture.

Still further,1a'n additional Vfeature Yof this invention is the provisionfof a filter having its lter elements formed of'eXpanded-,metal or the like having a plurality- -fof corrugations, which serves to increase the lint-holding capacitylof the? filter without liability of the filter becoming clogged or loaded up with such airborne particles aslintandthelike.- 1 i e Also, it is an important feature of this inventionzto so arrange the sheets or lter elements f that ther-corrugations of each sheet are trans--v verse with respect to adjacent sheets, thereby providing adequate space between the filtering surfaces toy secure a very low resistance to air now 'through the unit. Y

the principles of thepresent-inventionhave been incorporated. U

Figures 2 and 3 are `enlarged fragmentary sectional views, somewhat diagrammatic,innature,i

taken along'the lines 2-2 Yand 3-3 of .Figure 1^. Figure 4 is an enlarged fragmentary perspective ;view,-sh`owing the dust-catching-pockets.and the sharpened l.eliges that lare produced .during the process of expanding the -metal sheet, of which the lter element is made, into reticulated form. Figure 5 is a sectional view taken along the line 5-'5 of Figure 4.

Figure 6 is a fragmentary View of a portion of the metal-expanding die.

Referring rst to Figure 1, the lter incorporating the principles of this invention is shown as having a frame l formed of channel stock with the fianges 2 cut so as to permit folding the sections into a box-like form, the slitted flange portions being indicated at 3. The frame l encloses a plurality of expanded metal sheets formed of aluminum stock, there being, in one form of the angles to the corrugations of the next adjacent',-

sheet or sheets. After assembly, the sheets are connected together in any suitable Way, as by one or more aluminum wires or the like, which materially facilitates installation of the channel frame around the filter sheets, overlapping portions of the frame channel flanges being riveted or otherwise connected to complete the frame.

To form the expanded metal sheets mentioned above, dies are used which produce roughened or feathered edges and pockets. One of the portions of the upper die is shown in Figure 6, in which the shea-ring or slitting edge is indicated at |5, the working face of the die being grooved or serrated, as shown at I6. The die face is so shaped and the serrations I6 so formed that in operation the expanded metal mesh has the form and characteristics illustrated, by Way of V,example in Figure 4, which is enlarged several times actual size. Asshown in Figure4, thestrands I8 are slightly curved and `the strand-connecting `bars I 9 are curved or cupped, as at 2|, forming `the dust- `catching pockets mentioned above. Additionally, the serrations I6 on the slitting and stretching dies form roughened edges onthe lower side of the sheet when-the die is forced' threrethrough andalso on the upper `side of the portion of the sheet being severed from the stock. Such roughened or feathered edges are shown at l22 in Figure 4, and also in Figure 5.

In use, afterthe sheets or filter elements have been properly assembled and arranged in the frame and the latter locked in closed position by the rivet R (Fig. 1) or the like, adhesive material, usually oil of the proper viscosity, is brushed onto the faces of the filter. This material spreads throughout the entire interior structure of the filter elements, especially adhering to the pockets 2| and roughened edges 22, whereby dust, dirt and thev like in the airpassing through the filter impinge on the wettedv surfaces thereof and adhere thereto. Dust and the like collect on the roughened edges 22 and especially in the pockets 2| and are retained at such points until the filter becomes clogged with material and must be cleaned or renewed. It will thus be seen that the filter of the present invention has much more adhesive-retaining qualities than the ordinary Wire meshA filter.v Since the larger openings are at the intake YSide ofthe unit, only the larger particles, such as lint or other fibrous material, are caught by the filter 4elements 5 and/or 6. Finer dust, dirt, and the like, pass on into the lter and 4 are caught 'by the sections having the smaller openings.

Since both the frame and the filter sheets or elements are made of aluminum, the lter will not rust or corrode in the presence of humidity. or moisture, as may be encountered in Washed air-systemsl for example.

By virtue of the transverse corrugations formed in the filter sheets, lint and other similar material in quantities that might overload and clog ordinary flat filter elements, tend to collect in fthat the pockets 2| face upstream, as indicated in Figure 5.

While I have shown in the accompanying drawings and described above what is now considered to be the preferred embodiment of my invention, it is to be Yunderstood that my invention is not to be limited to the particular structure shown and,described above, `but that, in fact, widely different ,means' maybe utilized in the practice of the 'broader aspects of my invention.

What I claim and desire to secure by Letters Patent'is: n

A lter comprising a plurality of sheets of expandedA metal having openings formed by spaced apart bars and strands interconnecting end portions of adjacent bars, each strand and bar having a generally rectangular cross section, diagonally opposite edges of said strands and said bars being formed with a multiplicity of outwardly drawn small points, forming roughened or serrated portionsserving to increase the oil-holding capacity of the lter, and means holding the sheets vin assembled relation.

GLENN o. SMITH.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS '13,855 f 'Austria oct. 1o, 1917 

